[ RadSafe ] Re: LNT/threshold/hormesis - what do HPs really

[Muckerheide, James]

Andy, All,

Abel Gonzalez (and other LNT supporters) cleverly misrepresent the fact that
it would take a large number of cases to disprove the LNT ONLY if you assume
the LNT is true!  

See the following plot to indicate results of the presumed LNT (dotted line)
vs. the actual data at/below about 15 cGy (using in the larger 'Other
Provinces' data):

http://cnts.wpi.edu/RSH/Docs/Pollycove/Pollycove2000_Symposium/Image29.gif 

Look at the 1 cGy (1 rem) "limit" which indicates that it would indeed take
millions of people to demonstrate a difference between the LNT line AND THE
ZERO-EFFECTS LINE.  Here, the 15 cGy group is about 200 women (I'd have to
check the data table).

Note:  I will even accept the LNT below 1 cGy - if the LNT interpolation of a
straight line starts from the actual data at 15 cGy!!  :-)

Note further:  This study was claimed to be the most significant data in the
BEIR V report!  It is one of the 7 listed as the basis for the BEIR V
modeling!?

And:  The LNT mandate caused the authors to present this as "the LNT is the
better fit" (vs. the LQ fit) while ignoring their own data.  The original
NEJM paper presented this data in a table, but the data (without the fitted
line) was plotted and presented by Ted Webster as the 1992 NCRP meeting
annual Lauriston Taylor lecture!  

The study was quickly updated (1996) BUT with all of the data in the low dose
groups lumped into one point from 1 to 49 cGy to obfuscate these results.  In
questioning, on at least two occasions, the author said "They like straight
lines." 

There is additional discussion at Figure 6 in the paper:
http://cnts.wpi.edu/RSH/Docs/Pollycove2000_Symp_on_Med_Ben.htm 

You can get the full ref to Miller 89 and PubMed abstract at: 
http://tinyurl.com/awuum 

Regards, Jim Muckerheide
=========================


> -----Original Message-----
> From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
> Behalf Of A Karam
> Sent: Wednesday, July 20, 2005 12:57 PM
> To: Rainer.Facius at dlr.de; radsafe at radlab.nl
> Subject: RE: [ RadSafe ] Re: LNT/threshold/hormesis - what do HPs really
> 
> I have received several comments to this effect, to the point where it
> makes sense to post to the entire list.
> 
> In his 2004 Sievert Lecture, Abel Gonzalez presented a very interesting
> figure showing the number of research subjects needed to prove, or
> disprove LNT as a function of the dose each person received.  Using
> current epidemiological and statistical tools, he made a fairly
> convincing case that to show the presence or absence of effects at low
> levels of exposure - less than a rem - takes so many subjects that such
> studies are virtually impossible to perform or to fund.
> 
> So; epidemiological science seems unable to prove or disprove any
> particular model of radiation dose-response at low levels of exposure.
> Radiation biology seems able to point us towards an answer, but seems to
> somehow leave many people unsatisfied that studies of individual cells
> are applicable to entire organisms.  So, at present, I get the
> impression that no scientific community will be able to prove (or
> disprove) its case to the radiation safety and radiation biology
> community as a whole. In addition, we must admit that, even in the most
> limiting case (LNT), the risks from radiation do not warrant the public
> health precautions that are taken and funded - the radiation safety
> agenda (on a national and international scale) is driven by politics and
> opinion rather than science.
> 
> That being the case, I'm simply interested in knowing where the
> professional, well-informed opinions fall out.  We hear a lot of heated
> debate, but since the great majority of Radsafe members sit quietly at
> their computers, I have no idea how the radiation safety community as a
> whole feels on the matter.  And, let's face it, you're not going to get
> a true feeling for that in a public forum because so many feel
> constrained by peer pressure, employer requirements, not wanting to look
> like an idiot, and so forth.
> 
> Best regards,
> 
> Andy
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